Abstract
In the consideration of this subject I wish to distinguish between racial prognathism and pathologic types as illustrated by the case reported. Evolution is presumed to have been from the prognathous or forward-jawed type to the orthognathous or straight face, Mongolian or Caucasian type. The contraction from the prognathous jaws to the orthognathous has been a factor in the production of the irregularities of dentition so common in the higher races. Figure 1, shown through the courtesy of Professor Starr, represents a Taruscan Indian girl (Mexico) illustrating a racial type. With the occurrence of the recession of both jaws the teeth are crowded together. In the case of prognathism which is the subject of this report, only the lower jaw projects and therefore the occlusion of the teeth is very imperfect (Figs. 2 and 3). The incisal edges of the upper central incisors were five-eighths of an inch posterior to
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